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Chapter 7: Choosing Among MHC Technologies

Printed Wiring Boards Cleaner Technologies Substitutes Assessment: Making Holes Conductive

This chapter of the Cleaner Technologies Substitutes Assessment (CTSA) organizes data collected or developed throughout the assessment of the baseline non-conveyorized electroless copper process and alternatives in a manner that facilitates decision-making. First, risk, competitiveness, and conservation data are summarized in Section 7.1. This information is used in Section 7.2 to assess the net benefits and costs to society of implementing an alternative as compared to the baseline. Section 7.3 provides summary profiles for the baseline and alternatives.

Information is presented for eight technologies for performing the making holes conductive (MHC) function. These technologies are electroless copper, carbon, conductive ink, conductive polymer, graphite, non-formaldehyde electroless copper, organic-palladium, and tin- palladium. All of these technologies are wet chemistry processes, except the conductive ink technology, which is a screen printing technology.1 The wet chemistry processes can be operated using vertical, immersion-type, non-conveyorized equipment or horizontal, conveyorized equipment.2 Table 7.1 presents the processes (alternatives and equipment configurations) evaluated in the CTSA.

Table 7.1 MHC Processes Evaluated in the CTSAa

MHC Technology Equipment Configuration
Non-Conveyorized Conveyorized
Electroless Copper (BASELINE)

X

X

Carbon

X

Conductive Polymer

X

Graphite

X

Non-Formaldehyde Electroless Copper

X


Organic-Palladium

X

X

Tin-Palladium

X

X

a The human health and aquatic toxicity hazards and chemical safety hazards of the conductive ink technology were also evaluated, but risk was not characterized.

The results of the CTSA suggest that the alternatives not only have environmental and economic benefits compared to the non-conveyorized electroless copper process, but also perform the MHC function as well as the baseline. While there appears to be enough information to show that a switch away from traditional electroless copper processes has reduced risk benefits, there is not enough information to compare the alternatives to this process among themselves for all their environmental and health consequences. This is due to a lack of proprietary chemical data from some suppliers3 and because toxicity values are not available for some chemicals. In addition, it is important to note that there are additional factors beyond those assessed in this CTSA which individual businesses may consider when choosing among alternatives. None of these sections make value judgements or recommend specific alternatives. The actual decision of whether or not to implement an alternative is made outside of the CTSA process.

7.1 RISK, COMPETITIVENESS, AND CONSERVATION DATA SUMMARY [108K PDF file]

7.2 SOCIAL BENEFITS/COSTS ASSESSMENT [105K PDF file]

7.3 TECHNOLOGY SUMMARY PROFILES & REFERENCES [683K PDF file]


Footnotes

1. Only limited analyses were performed on the conductive ink technology for two reasons: 1) the process is not applicable to multi-layer boards, which were the focus of the CTSA; and 2) sufficient data were not available to characterize the risk, cost, and energy and natural resources consumption of all of the relevant process steps (e.g., preparation of the screen for printing, the screen printing process itself, and screen reclamation).

2. Conveyorized MHC equipment is a relatively new innovation in the industry, and is usually more efficient than non-conveyorized equipment. Many of the newer technologies are only being used with conveyorized equipment, while most facilities in the U.S. still use a non-conveyorized electroless copper process to perform the MHC function.

3. Electrochemicals, LeaRonal, and Solution Technology Systems provided information on proprietary chemical ingredients to the project. Atotech provided information on one proprietary ingredient. W.R. Grace was preparing to provide proprietary information on chemical ingredients in the conductive ink technology when it was determined that this information was no longer necessary because risk from the conductive ink technology could not be characterized. The other suppliers participating in the project (Enthone-OMI, MacDermid, and Shipley) declined to provide proprietary information.


Click here for an Adobe Acrobat PDF version of Chapter 7 in its entirety. [891K PDF file]

For Volume I in its entirety [4,508K PDF file]

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